1. Field of the Invention
The invention relates to sliding door or window latches, in particular to latches with anti-slam and anti-lift functions.
2. Description of Related Art
Sliding doors and windows are widely used in residential and commercial settings. Sliding doors and windows may include a single sliding panel moving relative to a frame, or two or more panels moveable relative to the frame. Latches are used to secure the sliding panels to the frame and/or to each other in order to provide a secure latched state for the door or window.
Latches for sliding doors and windows generally include a latch body that includes one or more hooks. The latch body is usually mounted to the sliding window or door panel, with a strike mounted either to the frame or to a second sliding window or door panel. The hooks rotate from a withdrawn position within the latch body to an extended position. In the extended position the hooks will engage with the strike, thereby securing the latch body to the strike and the sliding window or door panel either to the frame or the other sliding panel.
Sliding doors and windows can be slammed forcefully in use. If the latch hooks are extended from the latch body during forceful closing of the door, the latch mechanism can be damaged. Further, it is generally not possible to move the door to the fully closed position while the latch hooks are extended. For this reason sliding door and window latches sometimes include an anti-slam mechanism. This generally includes a mechanism mounted in the latch body that restricts motion of the latch hooks into the extended position, unless the latch body is in close proximity to the strike, i.e. unless the door is already closed. This mechanism can be actuated by a biased pin that extends from the latch body. As the latch body approaches the strike, the pin is forced to retract into the latch body. Retraction of the pin disengages the anti-slam mechanism and this removes the restriction on movement of the latch hooks.
Intruders sometimes attempt to lift sliding doors and windows off the latch hook. This is done by prying the latch hook upwards relative to the strike in an attempt to disengage the latch hook from the strike. To guard against this possibility, latches sometimes include formations on the latch body and strike that cooperate to restrict this vertical motion.
Reference to any prior art in this specification does not constitute an admission that such prior art forms part of the common general knowledge.
It is an object of the invention to provide an improved sliding door or window latch, in particular to provide an improved anti-slam, anti-lift mechanism, or at least to provide the public with a useful choice.